Creativity has received significant interest in variety of fields and disciplines with a major focus on individual level creativity. As more and more achievements started originating from groups, researchers turned their attention to creativity on group level. Current thesis explores the group creativity as well as flow experience in collaboration. It explores the group creativity phenomena and its correlates in different contexts, age groups and cultures. The overarching aim of the thesis is to extend our knowledge on group creativity and contribute to open questions in the field such as - How does (group) creativity develop? Which interpersonal and motivational processes play a role in group creativity? How can we measure group creativity? In four studies, the present research found that (social) flow can be explained by empathy and motivation of group members as well as domain of performance. To build on these results, the role of interpersonal processes in group creativity was explored with adults. While closeness was found to benefit group creativity, combination of closeness with perspective taking was harmful on creative performance. Moreover, with an aim to understand how group creativity develops, this thesis explored group creativity in children and adolescents from England and Turkey. Across these two samples, group creativity performance developed with age and advances in social perspective coordination was one mechanism explaining that development. Additionally, study conducted with Turkish children found task cohesion as a facilitator of group creativity. Major similarities in findings obtained from two samples implicated cultural universality in development of group creativity, however, slight differences in results pointed to the possibility of culture-specific differences in processes underlying group creativity. Finally, the current thesis contributed to literature by adopting and validating a collaborative story writing method as a promising measurement of group creativity. Overall, the studies presented in this thesis illustrate the role that interpersonal and motivational process play in group creativity practices of different age groups and cultures. Findings lead us to the next steps on the adventurous discovery of group creativity.